This invention relates to an automatic override system for modifying the operation of glass forming machinery.
The individual section or IS glass forming machine, which is well-known in the art, has a plurality of glass forming means integrated into a single plural section machine fed by a single source of molten glass. The sections are operated in synchronism in such relative phase relationship as to permit the several sections to acquire gobs in ordered sequence from a single gob feeder. Thus, as one of the sections is taking a gob from the gob feeder, another section is delivering a finished article to an output conveyor and other sections are engaged in various forming steps intermediate the taking of a gob and the production of the finished ware.
Further, it has been customary to provide two molds rather than one in each section of an individual section machine whereby a gob is received in a first mold called the blank or parison mold, for the initial process of forming a parison, followed by transfer of the parison to a second mold, called the blow mold, for final blowing of the article. By this means each section of the machine is operating simultaneously upon two work pieces. In order to control the operation of the various functional components of the glass forming machine, a means must be provided for actuating each of the elements in a preselected cyclic time format so that the operation of one element does not interfere with, but rather complements, the operation of the other components.
The several functional elements or components of the glass forming stations in the individual section machine are typically driven by pneumatic pressure which is controlled by an electronic timing circuit. An example of prior art controllers utilizing electronic timing means may be found in Quinn et al, U.S. Pat. No. 3,762,907 and Kwiatkowski et al, U.S. Pat. No. 3,969,703, both of which are assigned to the common assignee herewith. Other examples of prior art electronic controllers may be found in Croughwell, U.S. Pat. No. 3,905,793 and Mylchreest et al, U.S. Pat. No. 3,877,915. Each of these controllers typically includes a timing means for generating a machine cycle clock pulse train in synchronism with the operation of a machine being controlled, wherein the cycle clock pulses provide an instantaneous indication of the time elapsed in each cycle of operation of the machine. A storage unit such as a random access memory or a shift register stores the relative times in the machine cycles when each of the plurality of components of the machine are to be actuated. A comparator then compares the output of the pulse generator which indicates the time elapsed in each cycle with the stored values in the storage unit. When a comparison is made an actuating signal is generated for indicating that the functioning of the machine component is to be either started, stopped, or modified. To determine which machine component is to be actuated, an addressing means is provided which when enabled by the output of the comparator, selects the particular component which is to be actuated at that time in the machine cycle. A component operating command is then provided to the appropriate component to thereby control the operation thereof. These electronic controllers include systems for varying the time at which a particular machine component is to be actuated while the machine is operated. Further, these machines include systems for initiating a starting or stopping sequence at any time during the machine cycle so that once a starting or stopping sequence is initiated, the machine is controlled according to a preselected starting or stopping cycle so that the machine can be safely and efficiently turned on or shut down.
A drawback of the prior art is that if a particular machine component or the material being operated on, i.e., the molten glass or parison, is not in the proper position at any given time, expensive molding equipment can be damaged and production time lost. Further, when each individual section machine is being started up, the machine must be carefully monitored manually in order to insure that each component is in a proper operating position. This results in expensive manpower requirements.
Accordingly, it is an object of this invention to provide a glass forming machine having an automatic override system for continuously monitoring the glassware machine and for permitting correction of the position of the respective components of the machine if not in the proper operating position.